scholarly journals Phosphate-stimulated breakdown of 5′-methylthioadenosine by rat ventral prostate

1969 ◽  
Vol 115 (2) ◽  
pp. 241-247 ◽  
Author(s):  
A E Pegg ◽  
H G Williams-Ashman
Keyword(s):  
Inorganic Phosphate ◽  
Ventral Prostate ◽  
Soluble Enzyme ◽  
Phosphate Ions ◽  
Rat Ventral Prostate ◽  
Absolute Requirement ◽  
Mammalian Tissues ◽  
Nucleoside Metabolism ◽  
Nucleoside Phosphorylases

A soluble enzyme preparation catalysing the release of adenine from 5′-methylthioadenosine was purified some 30-fold from extracts of the rat ventral prostate. This reaction was completely dependent on addition of inorganic phosphate ions to the assay medium. This absolute requirement for phosphate ions suggests a phosphorolytic cleavage mechanism. After acid treatment, the other product of the reaction appeared to be 5-methylthioribose. The actions of some other well-characterized enzymes of nucleoside metabolism of 5′-methylthioadenosine were also investigated; purified purine nucleoside phosphorylases from calf spleen and human erythrocytes did not attack 5′-methylthioadenosine. The role of 5′-methylthioadenosine in mammalian tissues is discussed.

Evidence For A Non-Androgenic Role of Testis and Epididymis in Androgen-Supported Growth of the Rat Ventral Prostate

1992 ◽  
Vol 148 (2 Part 1) ◽  
pp. 432-440 ◽  
Author(s):  
Frank S. Darras ◽  
Chung Lee ◽  
Shankar Huprikar ◽  
Alfred W. Rademaker ◽  
John T. Grayhack
Keyword(s):  
Ventral Prostate ◽  
Rat Ventral Prostate

scholarly journals The androgenic regulation of superhelical-DNA nicking-closing enzyme in rat ventral prostate

1981 ◽  
Vol 196 (1) ◽  
pp. 195-202 ◽  
Author(s):  
J D Filipenko ◽  
P S Rennie ◽  
N Bruchovsky
Keyword(s):  
Enzyme Activity ◽  
Dna Synthesis ◽  
Chromatin Structure ◽  
Structural Organization ◽  
Time Course ◽  
Ventral Prostate ◽  
Rat Ventral Prostate ◽  
Dna Nicking ◽  
Androgenic Regulation

The activity of superhelical-DNA nicking-closing enzyme (NC enzyme) was measured in nuclei from rat ventral prostate by a fluorimetric assay based on the binding of ethidium bromide to supercoiled phage-PM2 DNA. The nuclear concentration of NC-enzyme activity declined rapidly after castration, although this response could be prevented by daily administration of dihydrotestosterone. The low NC-enzyme activity in involuted prostates (10% of normal) was restored to normal after 8-10 days of treatment with androgen. In the regenerating prostate the time course of restoration of NC-enzyme activity was not in phase with that of DNA synthesis. Examination of nucleosome repeat lengths and the arrangement of nucleosomes along the chromatin fibre revealed no differences in the structural organization of chromatin in prostates with high or low NC-enzyme activity. Together, these results suggest that the major role of NC enzyme is related to the onset and maintenance of differentiation in the prostate and that the activity of this enzyme is not expressed through gross alterations in chromatin structure.

THE ROLE OF THE STEROID-SENSITIVE CATION-DEPENDENT ATPASE IN HUMAN PROSTATIC TISSUE

1972 ◽  
Vol 54 (3) ◽  
pp. 375-385 ◽  
Author(s):  
W. E. FARNSWORTH
Keyword(s):  
Reductase Activity ◽  
Benign Prostatic Hypertrophy ◽  
Enzymic Activity ◽  
Ventral Prostate ◽  
Hormonal Stimulation ◽  
Dependent Atpase ◽  
Rat Ventral Prostate ◽  
Steroid Sensitive ◽  
Steroid Binding

SUMMARY The purposes of this study were: (1) to determine if a (Na+ + K+)-dependent, ouabain-sensitive, androgen-responsive ATPase is present in the microsomal fraction of the human prostate as it is in the rat ventral prostate; (2) to determine the degree and nature of interaction and interdependence of the ATPase with the steroid-binding and steroid-metabolizing activities of the prostate and, also, with the histological characteristics of the gland. The results indicate that ATPase which shows particular responsiveness to 5α-dihydrotestosterone, 5α-androstane-3α,17β-diol and dehydroepiandrosterone is present. The microsomes, which contain this enzymic activity, show relatively high affinity for the active steroids and for oestradiol-17β. The intrinsic steroid-sensitive, cation-dependent ATPase activity varies widely from gland to gland in parallel with the steroid binding and 3α-hydroxysteroid dehydrogenase activity. In comparisons of the enzymatic complements of glands with different histological features, the concentration of 4-en-3-oxosteroid-5α-reductase activity in tissue showing predominantly epithelial hyperplasia was greater than that in normal or carcinomatous glands or glands with stromal hypertrophy. The possible role of the ATPase as a mediator of hormonal stimulation, and the implications of the findings to an understanding of the development of benign prostatic hypertrophy, are discussed.

EFFECT OF SOME SYNANDROGENS AND ANTIANDROGENS ON THE CONVERSION OF TESTOSTERONE TO DIHYDROTESTOSTERONE IN THE CULTURED RAT VENTRAL PROSTATE

1976 ◽  
Vol 81 (2) ◽  
pp. 398-408 ◽  
Author(s):  
Risto Johansson
Keyword(s):  
Culture Medium ◽  
The Other ◽  
Ventral Prostate ◽  
Testosterone Metabolism ◽  
Other Hand ◽  
Rat Ventral Prostate ◽  
Target Organs

ABSTRACT The actions of prolactin, insulin and cortisol on the conversion of testosterone to dihydrotestosterone in the cultured rat ventral prostate were examined in conditions in which they have been demonstrated to act synergistically with testosterone on the macromolecule synthesis of the prostate. On the other hand oestradiol, progesterone and cyproterone were tested similarly in conditions where they have been shown to be effective antiandrogens. The metabolism of testosterone to dihydrotestosterone was found to be extremely rapid and approximately 70 % of the radioactive steroids in the tissue was dihydrotestosterone from 5 min onwards, but only insignificant amounts of dihydrotestosterone were found in the culture medium during the first hour. Physiological concentrations of the synandrogens did not alter the metabolism of testosterone or the accumulation of the steroids into the tissue. Oestradiol, progesterone and unlabelled testosterone in a 500-fold concentration markedly reduced the conversion of tritiated testosterone to dihydrotestosterone while cyproterone and dihydrotestosterone had no effect. The possible role of other hormones in the alteration of testosterone metabolism in the target organs as the mechanism of synandrogenic or antiandrogenic action is discussed.

scholarly journals Specific inhibition of the enzymic decarboxylation of S-adenosylmethionine by methylglyoxal bis(guanylhydrazone) and related substances

1974 ◽  
Vol 139 (2) ◽  
pp. 351-357 ◽  
Author(s):  
A. Corti ◽  
C. Dave ◽  
H. G. Williams-Ashman ◽  
E. Mihich ◽  
Amelia Schenone
Keyword(s):  
Potent Inhibitor ◽  
Aliphatic Amines ◽  
Ventral Prostate ◽  
Specific Inhibition ◽  
Adenosylmethionine Decarboxylase ◽  
Related Substances ◽  
Rat Ventral Prostate ◽  
Mammalian Tissues ◽  
Rat Prostate

Methylglyoxal bis(guanylhydrazone) {1,1′-[(methylethanediylidene)-dinitrilo]diguanidine} is a very potent inhibitor of putrescine-activated S-adenosylmethionine decarboxylases from many different mammalian tissues, including sublines of mouse L1210 leukaemia that are resistant to the drug as well as sublines that are sensitive. The inhibition of purified rat ventral prostate S-adenosylmethionine decarboxylase is competitive with respect to the S-adenosylmethionine substrate, and is much greater in the presence than in the absence of the activator putrescine. Inhibition by the drug depends, among other things, on the nature of the aliphatic amines that can serve as stimulators of rat prostate S-adenosylmethionine decarboxylase. Effects of some congeners of methylglyoxal bis(guanylhydrazone) on the enzyme are described.

scholarly journals Androgen-Induced Regrowth in the Castrated Rat Ventral Prostate: Role of 5α-Reductase1

Endocrinology ◽  
1999 ◽  
Vol 140 (10) ◽  
pp. 4509-4515 ◽  
Author(s):  
A. Stuart Wright ◽  
Robert C. Douglas ◽  
Lynn N. Thomas ◽  
Catherine B. Lazier ◽  
Roger S. Rittmaster
Keyword(s):  
Ventral Prostate ◽  
Rat Ventral Prostate

3α-HYDROXYSTEROID DEHYDROGENATION IN SUBCELLULAR FRACTIONS OF RAT VENTRAL PROSTATE AND OTHER TISSUES

1965 ◽  
Vol 33 (3) ◽  
pp. 353-363 ◽  
Author(s):  
MARION B. R. GORE ◽  
D. N. BARON
Keyword(s):  
Seminal Vesicle ◽  
Chromatographic Method ◽  
Ventral Prostate ◽  
Rat Tissues ◽  
Soluble Enzyme ◽  
Experimental Conditions ◽  
Widespread Occurrence ◽  
Rat Ventral Prostate ◽  
Soluble Fractions

SUMMARY Dehydrogenation of androsterone, catalysed by both particulate and soluble fractions of rat ventral prostate, has been demonstrated in vitro by spectrophotometric and chromatographic methods. A difference has been observed between dehydrogenases in the particulate and soluble fractions in their acceptance, under uniform experimental conditions, of the 5α and 5β isomers, androsterone and aetiocholanolone, as substrate. The particulate enzyme dehydrogenates androsterone under conditions in which aetiocholanolone is not dehydrogenated, whereas the soluble enzyme utilizes equally androsterone and aetiocholanolone as substrate. An examination of other rat tissues by the chromatographic method has confirmed the widespread occurrence of the soluble dehydrogenase. Particulate dehydrogenase resembling the prostatic enzyme was detected in seminal vesicle and kidney.

scholarly journals The relationship between inhibition of plasminogen-activator activity and prostatic involution

1988 ◽  
Vol 252 (3) ◽  
pp. 759-764 ◽  
Author(s):  
P S Rennie ◽  
J F Bowden ◽  
N Bruchovsky ◽  
H Cheng
Keyword(s):  
Tranexamic Acid ◽  
Inverse Correlation ◽  
Fold Increase ◽  
Cell Loss ◽  
Cell Number ◽  
Ventral Prostate ◽  
Rat Ventral Prostate ◽  
High Doses

The role of plasminogen activators (PAs) as potential mediators of involution of the rat ventral prostate was investigated by using an approach involving the administration in vivo of anti-PA drugs. The prostates of castrated rats, which had been injected daily for 7 days with the anti-PA drugs 6-aminohexanoic acid, tranexamic acid, aprotinin and cortisol, were assayed for PA activity, weight and cell number. In the prostates from the castrated controls, there was a 10-fold increase in the mean PA activity and a 7-fold decrease in cell number relative to that of the non-castrated animals. Although this rise in enzyme activity could be decreased to some extent by all the drugs except aprotinin, only treatment with high doses of tranexamic acid or cortisol had a statistically significant effect. A similar pattern was observed with respect to the relative potency of the drugs in preventing the loss of prostatic weight and cell number after castration. The effects of cortisol were dose-dependent, with complete inhibition of both the rise in PA activity and cell loss occurring at a dose of about 15 mg/day. Since the concentration of the principal intranuclear androgen, dihydrotestosterone, was the same in the prostates from treated and untreated castrated rats, the effects of cortisol are not due to increased retention of this androgen. Rather, the high inverse correlation (r = 0.86) between the cellular concentration of PA activity and the cell population of the prostate implies that PAs are directly associated with prostatic involution and that cortisol, and to a lesser extent tranexamic acid, blocks the involution process through inhibition of PAs.

Sign in / Sign up

Export Citation Format

Share Document